The primary goal of this Redes En Accidn pilot proposal is to canry out a randomized controlled trial (RCT) comparing quit rates of a Spanish/English stop smoking Web site to those of a no-lnten/enfion control. The University of California, San Francisco (UCSF) Stop Smoking research Web site has enrolled a diverse, internafional sample of more than 47,000 smokers into several randomixed trials since 2000. However, we have not included a no-intervention condition in these trails to date. Our published absfinence rates at one year are 20%, but obtaining evidence that our intervenfions yield higher absfinence rates than a no-intervenfion control is the next logical step. Furthermore, although our Web site was designed in English and Spanish, our success in attracting the U.S. Hispanic/Latino (HL) population in either language has been limited, so this project only will recruit HL smokers and add new recruitment methods to do so. The study will randomize HL participants to one of two condifions, an inten/enfion condition (immediate) and a no-intervenfion control (delayed). For the control, a 6-month Delayed treatment condition (DC) will inform participants that we are tesfing whether HL smokers who are motivated enough to seek Internet information on smoking cessafion can quit on their own at the same rate as smokers who are given access to an interacfive stop smoking Web site. We will provide them a basic online smoking cessafion packet(1) from the U.S. Public Health Service (USPHS). For our intervention, the Immediate treatment condition (IC) is the UCSF Spanish/English Stop Smoking research Web site (vwvw.stoDsmokina.ucsf.edu) that provides smokers all elements tested in eariier trials: 1) a Web version of a National Cancer Institute-designated evidence-based intervenfion, the Guia para Dejarde Fumar2; 2) e-mail reminders to return to the site fimed to individually set quit dates; 3) a mood management smoking cessafion intervenfion; and 4) a virtual group (an asynchronous bullefin board designed to let participants provide mutual support). All IC participants also will receive the USPHS cessafion packet from the DC control to ensure that the interactive Web site is the only difference between the condifions. We will randomize 608 HL smokers in English or Spanish stratified by gender within language group. Participants will be followed at 1, 3, and 6 months after randomizafion to obtain self-reported prolonged absfinence and 7- and 30-day time point prevalence rates. E-mail reminders will be sent to remind participants to return to the site to complete follow-up surveys. The main comparison measure will be cessafion at 6 months from original randomization. DC participants will be able to access the interactive site after finishing the 6-month follow-up. We plan to attract Spanish-speaking HL participants to our Web site using Spanish-language TV and radio interviews and PSAs, Spanish-language Google ads and networking with U.S. cessation groups.